Railguns are too powerful to sound like a tiny laser blast. They need to sound powerful, like an actual railgun for example. If you agree, cool. If you dont, they still need new sound effects.

While powerful, they shouldn't have a "big" sound. Maybe more of a buzzy electric quality would help, but I'm mostly okay with how they are now.

This sounds like a Suggestion, so I am moving it to that forum.

A crackling electrical arc sound for firing and a loud metal-on-metal clank noise for the impact seems appropriate given the description of the weapon.

I rather like the <plink!> sound they make when they hit you. Its subtle but distinct. If they don't hit you, I don't think you should be able to hear it any more distinctly than a current miss. From the rail-firer's point of view, a new sound would be fun, as long as it doesn't give away the fact that you're using rails to your opponent. Nailing someone with a rail while masking it among the shots of another weapon is part of the surprise.